Method of detecting carious tissue



United States Patent 3,279,068 METHOD OF DETECTING CARIOUS TISSUE Marvin M. Stark, Los Altos, Calif., assignor to Barnes- Hind Pharmaceuticals, Inc, a corporation of California No Drawing. Filed Ian. 23, 1964, Ser. No. 339,608 3 Claims. (Cl. 167--84.5)

This invention relates to a method of detecting carious tissue and dental calculus.

In the preparation of teeth prior to filling, and in similar dental operations, it is highly important that all of the cations dentinal tissue be removed and that a minimum of sound dentinal tissue be removed. Since there can be little difference visually, between carious and sound tissue, it is often difiicult to make certain that all carious tissue is removed without the removal of an excessive amount of sound tissue. Similarly, it is advan- .tageous in cleaning teeth that calculus be disclosed.

The present invention relates to a disclosing agent which makes a vivid contrast either in ordinary visual light or in ultraviolet light between sound dentin tissue and carious dentin tissue and also discloses the presence of calculus.

In accordance with the present invention, it has been found that 9-arninoacridine and its hydrochloride are unique agents for disclosing the presence of dental caries and calculus.

In utilizing the compounds of this invention, it is only necessary to apply a small amount to the area in question. The 9-aminoacridine or its hydrochloride stains differentially and has a distinctive dark brown color in the presence of carious tissue or calculus but has a light yellow color on sound tissue in either visual or ultraviolet light. Therefore, it is quite easy to distinguish between sound tissue and carious tissue or calculus.

In accordance with a preferred method of carrying out the invention, it is only necessary to prepare an aqueous solution of the 9-aminoacridine hydrochloride, preferably utilizing deionized water. Solutions containing 9- aminoacridine hydrochloride and water in ratios of from 1:100 to 120,000 can be employed. However, it is generally preferred to prepare a relatively concentrated solution containing about one part of the 9-aminoacridine hydrochloride to 500 parts by weight of water.

Various other compositions can be utilized in carrying out the invention. Thus, the base 9-aminoacridine itself can be dissolved in a 50-50 alcohol-water mixture and used instead of the hydrochloride. The compounds can also be incorporated in gels such as aqueous gels containing from 0.25% to 2.5% of methyl cellulose or vegetable gums, or can be incorporated in lozenges, chewing gums, aerosols or similar compositions.

Although the Q-aminoacridine hydrochloride may be employed by itself as an aqueous solution, it is desirable in many instances to add additional agents such as nonionic or cationic surfiactants to increase its wetting ability or preservatives to increase the storage stability of sol-u- I tions after opening. Suitable wetting agents include henzalkonium chloride and polysorbate 80, U.S.P. (Tween 80), while suitable preservatives include benza-lkonium chloride, phenyl mercuric acetate, phenyl mercuric nitrate, chlorobutanol, esters of parahydroxy benzoic acid, and

the like. Generally speaking, it is preferred to package the solutions in a single usage container. In such instances, it is unnecessary to employ a preservative.

Preferably, the solution is employed at a pH of trout 5 to 7 since at a higher 'pH the material tends to precipitate out of solution, while at a lower pH there is a traumatic elTe-ct on dental tissue.

The following is a preferred composition:

0.2% by weight 9-arninoacrid-ine hydrochloride; 0.1% benzalkonium chloride; and 99.7% de-ionized water.

It is ordinarily not necessary to render such a solution isotonic, but if this is desired, adjustment should be made with non-ionizable materials such as glycerol, sorbitol, urea or the like.

The material of the present invention is compatible with local anesthetics.

The exact mechanism by which the present invention works is not understood. Many materials possess fluorescent properties yet have no value as disclosing agents.

I claim:

1. The method of disclosing carious dentinal tissue and calculus comprising applying to a suspected area a small amount of a member selected irom the group consisting of 9-aminoacridine hydrochloride and 9+amin acridine.

2. The method of claim 1 wherein an aqueous solution is utilized containing from 1:100 to 120,000 parts of 9- aminoacridine hydrochloride, the balance being water.

3. The method of claim 1 wherein a solution is utilized containing about 1 part of 9-aminoacridine hydrochloride to 500 parts water.

References Cited by the Examiner UNITED STATES PATENTS 2,151,495 3/ 1939 Bender 16793 References Cited by the Applicant UNITED STATES PATENTS 1,629,873 5/ 1927 Jensch. 1,760,781 5/ 1930 Schulemann et al. 1,766,403 6/ 1930 Schulemann et al. 1,889,704 11/ 1932 Schulem-ann et al. 2,092,131 9/ 1937 Mietzsch et all. 2,113,357 4/ 1938 Mietzsclh et al. 2,121,207 6/1938 Mietzsch et a1. 2,124,590 7/ 1938 Reed. 2,155,501 4/ 1939 Maiser. 2,334,348 11/ 1943 Miglarese. 2,488,904 11/1949 Falk. 2,531,010 11/ 1950 Surrey. 2,718,487 9/ 1955 Marx. 3,019,227 1/ 1962 Erner. 3,067,137 12/ 1962 Schmulling. 3, 122,553 2/ 1964 Seneca. 3,149,068 9/ 1964 Biedernran et al.

RICHARD A." GAUDET, Primary Examiner.

ROBERT E. MORGAN, Examiner. 

1. THE METHOD OF DISCLOSING CARIOUS DENTIAL TISSUE AND CALCULUS COMPRISING APPLYING TO A SUSPECTED AREA A SMALL AMOUNT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF 9-AMINOACRIDINE HYDROCHLORIDE AND 9-AMINOACRIDINE. 